1. Technical Field
The present invention relates to an arrangement for internal combustion engines of the piston engine type having at least one row of cylinders. The arrangement has at least one fuel injector for each cylinder and at least one intake manifold for admission of air to the cylinders.
2. Background Art
Nearly all vehicles are equipped with an internal combustion engine or diesel engine. Today""s internal combustion engines, which run on gasoline, are provided with fuel injectors in contrast to carburetors for older engines. This is due to the increasingly stringent requirements regarding exhaust gas. An engine that has become more common recently is one having injectors that injects the fuel directly into the cylinder, known as direct injection. This type of engine permits lean running. However, direct injection engines have a construction-related problem in finding room on the engine""s cylinder head for the injectors and their admission lines, together with intake manifolds and other lines arranged around the cylinder head. The intake manifolds themselves take up a substantial amount of room, requiring perhaps several ports per cylinder, exhaust gas recirculation (xe2x80x9cEGRxe2x80x9d) inlets, valves, and pipes with selectable airways. In this context, use is often made of a fuel pipe system having a feed pipe to the side of the engine and narrow lines from the feed pipe to the injectors. These are relatively costly constructions since the demands on compactness and strength in this environment are high. Direct injection is also found on diesel engines, which have similar problems.
The present invention provides a solution to the above problems. In the invention, the inlets of the fuel injectors are connected to a fuel channel arranged in the intake manifold. The fuel channel is advantageously integrated in the intake manifold construction, with the inlets of the injectors preferably connected to openings adapted for them in the intake manifold.
A particularly advantageous embodiment has the intake manifold divided into two parts. The first part accommodates the fuel channel and the attachments to the fuel injectors, and the second part constitutes the rest of the intake system with, inter alia, the pipes. At the end facing away from the engine, the intake manifold may be designed with an attachment to an air-cleaning system or the like. One advantage of dividing an intake manifold in two is that the first part can be made of a material well suited for the special material treatment that is needed, while the other part can be made of a material with lower requirements, i.e., a less expensive material. The first part may be coupled to the fuel injectors with their associated demands, such as leak tightness and, therefore, surface fineness in the openings where the injectors are attached. The handling of the work pieces during material treatment is also made easier by the fact that the part which is treated is smaller than a complete intake manifold, e.g., if the material is to be treated in a furnace. It is also expedient to accommodate in the first part valves for swirl effect, since assembly is simpler.